The procedure is recommended for high-risk women before the age of 40. Jolie's mother died of cancer at the age of 56.

According to People: "Some doctors recommend patients undergo the surgery by age 40 or when a woman is done having children, though it may trigger early menopause."

Jolie, who is 37, will no longer be able to have children after the surgery.

Jolie and her fiancé, Brad Pitt, have three biological children and three adopted children - all under the age of 11.

Jolie explained in her op-ed that had the mastectomy so "I can tell my children that they don't need to fear they will lose me to breast cancer".

Jolie's decision has been praised widely. Pitt said: "Having witnessed this decision firsthand, I find Angie's choice, as well as many others like her, absolutely heroic. I thank our medical team for their care and focus."

Her estranged father, Jon Voight, said: "I was as surprised as anyone and deeply moved by the way she's handled this. She's a very extraordinary person. The way she examined it and what she shared."